Fact O' The Day

I don't know the source, but I heard this one at work:
A typical household pillow is home to about 2000 house dust mites, which in
turn excrete about 20 pellets of feces a day. It is estimated that a
6-year-old pillow will have approximately one-tenth of its weight comprising
of old human skin, dead and living mites, and mite dung.
Sleep well.